Field
The disclosure relates to a display device and a manufacturing method thereof.
Description of the Related Technology
A display device, such as for example a liquid crystal display (LCD), an organic light emitting diode (OLED) display, and an electrophoretic display, includes a field generating electrode and an electro-optical active layer. For example, the LCD device includes a liquid crystal layer as the electro-optical active layer. The field generating electrode is connected to a switching element such as a thin film transistor to receive a data signal, and the electro-optical active layer converts the data signal into an optical signal to display an image.
Among the display devices, since the organic light emitting diode (OLED) display as a self-light emitting type does not require a separate light source, it is advantageous in terms of power consumption, and a response speed, a viewing angle, and a contrast ratio thereof are excellent.
The organic light emitting diode (OLED) display includes a plurality of pixels such as red pixels, blue pixels, green pixels, and white pixels, and may express full colors by combining the pixels. Each pixel includes an organic light emitting element, and a plurality of thin film transistors for driving the organic light emitting element.
The light emitting element of the organic light emitting diode (OLED) display includes a pixel electrode, an opposing electrode, and a light emitting layer positioned between the two electrodes. One of the pixel electrode and the opposing electrode is referred to as an anode, and the other electrode a cathode. An electron injected from the cathode and a hole injected from the anode are coupled with each other in the light emitting layer to form an exciton, and the exciton emits light while discharging energy. The opposing electrode is formed throughout a plurality of pixels to transfer a predetermined common voltage.
In display devices, when impurities such as moisture or oxygen flow into the display device from an ambient environment, oxidization, releasing, and the like of the electrode occur, and as a result, a lifespan of the device is shortened or light emission efficiency may deteriorate, and problems such as deformation of a light emitting color may occur.
Accordingly, when the display device is manufactured, sealing is performed so that an internal element is separated from the outside to prevent impurities such as moisture from penetrating. As such a sealing method, in the case of the organic light emitting diode (OLED) display, may be generally, a method of laminating a layer including an organic polymer such as polyethylene terephalate (PET) on a completed lower substrate, a method of forming a cover or a cap on an encapsulation substrate and sealing an edge of a cover lower substrate and the encapsulation substrate with a sealant, or the like.
The above information disclosed in this Background section is only for enhancement of understanding of the background and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.